Reinforced, three zone microporous membrane
AssigneeCuno Incorporated
InventorsMark T Meyering, Jack H. Vining, Jr., C. Thomas Badenhop
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Abstract
A three zone, reinforced, continuous, geometrically symmetrical microporous membrane including a porous support material encapsulated within a middle zone disposed between an upper zone and a lower zone wherein at least one of the three zones has a pore size at least about twenty (20%) percent greater than the pore size of the other two zones is disclosed. Apparatus and methods for fabricating three zone reinforced, continuous, geometrically symmetrical, microporous membrane are also disclosed.
Claims75
A three zone, reinforced, continuous, geometrically symmetrical, microporous membrane prepared by a process comprising the acts of:
- providing a porous support material;
- providing first, second, and third polymeric dopes, the first dope being formulated to produce a quenched polymeric layer having a pore size which differs from quenched layer pore sizes obtained from at least one of the second and third dopes;
- substantially impregnating the porous support material with the first polymeric dope;
- coating the second dope over a first side of the impregnated porous support material such that the first and second dopes intermingle at an interface between the first and second dopes;
- coating the third dope over a second side of the impregnated porous support material such that the first and third dopes intermingle at an interface between the dopes;
- and
- quenching the coated substantially impregnated support material thereby forming the reinforced, continuous, geometrically symmetrical three-zoned microporous membrane, the microporous membrane comprising:
- a middle membrane zone having a first pore size, the middle zone comprising the porous support material and a microporous polymer derived from quenching the first polymeric dope;
- a second membrane zone having a second pore size, the second zone comprising a microporous polymer derived from quenching the second polymeric dope upon the first side of the substantially impregnated porous support material;
- and
- a third membrane zone having a third pore size, the third zone comprising a microporous polymer derived from quenching the third polymeric dope upon the second side of the impregnated porous support material, wherein the first pore size being at least about 20% greater than at least one of the second and the third pore size.
A three zone, reinforced, continuous, geometrically symmetrical microporous membrane prepared by a process comprising the acts of:
- providing a porous support material;
- providing fist, second, and third polymeric dopes, the first dope being formulated to produce a quenched polymeric layer having a pore size which differs from quenched layer pore sizes obtained from at least one of the second and third dopes;
- substantially impregnating the porous support material with the first polymeric dope;
- coating the second dope over a first side of the impregnated porous support material such that the first and second dopes intermingle at an interface between the first and second dopes;
- coating the third dope over an opposite side of the impregnated porous support material such that the first and third dopes intermingle at an interface between the dopes;
- quenching the coated support material with a quenching means, thereby forming the reinforced, continuous, geometrically symmetrical three-zoned microporous membrane, the microporous membrane comprising:
- a middle membrane zone having a first pore size, the middle zone comprising the porous support material and a microporous polymer derived from quenching the first polymeric dope;
- a second membrane zone having a second pore size, the second zone comprising a microporous polymer derived from quenching the second polymeric dope upon the first side of the impregnated porous support material;
- a third membrane zone having a third pore size, the third zone comprising a microporous polymer derived from quenching the third polymeric dope upon the second side of the impregnated porous support material;
- the first pore size being at least about 20% greater than the second pore size;
- and,
- the first pore size being different from the third pore size.
Dependencies are inferred from the claim text.